Sparking plug.



T. E. PONSOT.

SPARKING PLUG.

APPLICATION r1150 JUNE 4.1917.

Patented Dec.11,'1917..

. Fig.5.

Fig-4 IA b. llrlwlfl INVAwroR T/zegnhle El /2. 51s Ponsaa plug.

THEOPHILE ELP HEGE PONSOT, OF-PARIS. FRANCE.

srnnxme PLUG.

Specification of Letters Patent.

Patented Dec. 11,191'7.

Application flled June 4,1917. s mino. 172,695.

To all whom it may concern:

Be it known that I, THEOPHILE ELPHEGE PoNso'r, a citizen of the Republicof France, and resident of Paris, in the Republic of France, haveinvented new and useful Iin-v provements in Sparking Plugs, of which thefollowing is a specification.

The present, invention has for its :object a sparking plug which is ofvery simple con- 'struction, does not include any packing of asbestos orother material, and is constructed in such a manner as to permit notonly good insulation of the central electrode but also cooling of theupper part of the plug, and more especially of this central electrode,by establishing an air current through the lug upwardly, and about thecentral electro e.

- The improved sparking plug is characterized essentially by a centralelectrodeinsulatedfrom the metal body at its lower part by an insulatorsleeve in the form of a truncated cone fitting into the tubular part ofthe body which is of corresponding. form internally, and at its upperpart bya hell or capof insulating material.

Apertures are formed in the body and at the upper part of the cap in amanner such as to enable air to circulate upwardly in the interior ofthe cap and cool the central electrode. The central electrode is alsoprovided with a' head abutting against the insulating sleeve andprotecting the same from the hot flames caused by the ignition, therebyincreasing the life of the plug.

'The invention is shown by way of example in the accompanying drawing,wherein:

Figure 1 shows an elevation of my spark 1g. 2 is an under s de view ofthe same; and v Fig. 3 is a vertical section through the As shown, thesparking plug comprises a metal body o socket a provided with a screwthreaded tubular part b which enables" the .plug to be fixed on aninternal explosion engine. Thetubular part b is internally of the formof a truncated cone, of which the part of smaller diameter is arrangedat the upper part of the member 6. In the tubular part b there fits aninsulator sleeve 0 surrounding a rod (1 of the central electrode. Theinsulator sleeve chas a'lower'conical tfitting into the seat of the sameshape ormed by the tubular'part b. It has also an upper cylindrical partprojecting above cent end 0 the insulator sleeve 0.

the socket. The insulator sleeve 0 is formed by washers of mica fittedon to-the rod d which is already insulated by itsfitting into a tube 0also of mica. The washers hear at the lower part of the rod (1 on ametal disk which may form an integral part of the rod or be retainedthereon by a mushroom-head v d. The mica washers are tightened up in apress on the rod and are held in position on the rod 03 by a washer l ofivorine, fibrine or similar material, and also by a nut 10 which isthreaded on the rod and which is embedded in the above mentionedmaterial. A bell or cap -6 surmountsthe body a. It bears at itsupperpart a nut o which is in threaded engagement with the rod 1) of thecentral electrode, and by means of which said cap is secured in place.The cap has a reduced end which fits into a recess a formed in thesocket a. The rod receives also above the cap a Washer 17 and a lock nut2. By reason of the height of the cap e the upper exposed part of therod-d of the central elec-' trode is a considerable distance from themass of metal formed by the body a, thereby preventing the production ofexternal sparks when the end of the plug is subjected to high pressurein the interlor of the cylinder.

As mentioned above, the lower part of this central electrode is formedby a metal disk I: which has an inner inwardly tapering face, aainstwhich face abuts the adj a- This engagement ofthe end of the insulatorsleeve 'with the disk protects the end of the elecface arranged on thesame plane as the end A distance from the internal circumference of thetubular part b and'forming therewith a gap. The lower end of theinsulator sleeve 0 1s provided over all of its periphery with a beveledsurface'c? arranged in the opposite direction to the bevel is. These twobevels form an annular chamber (1 wherein residue from the combustion ofthe explosive mixture may lodge. This annular chamber hav-' ing arestricted inlet formed by the elec-' trodes prevents the hightemperature present in the cylinder from entering into said chamber andaffecting the end of the insulator which terminates therein.

In my improved sparking plug the internal air chamber formed in the bodya is very deep and the holes 71 at the periphery of the body open at thebase Oif this chamber. Moreover, the holes j formed in the cap 6 arearranged at the upper partof this cap. This arrangement causes an upwardair current through the air chamber and about the upper part of thesleeve and the exposedportion of the central electrode located withinthe said. chamber.

From the above description it will be seen that the plug is formed offew parts which can be easily and quickly taken apart as, for example,by removing the nut p and washer the central electrode can be withdrawnwith its insulator sleeve from the forms'a circular gapv with the wallof the upwardly tapering opening in the body, said circular sparkinghead tapering in the same direction as the opening but having a greaterobliquity, whereby a chamber is formed by the tapers in the body, thecircular head'and the lowerportion of the insulator sleeve.

2. In a spark plug, a metal body, a cen-' tral electrode having acircular sparking head presenting an inwardly tapering face,

an insulator sleeve having a tapering end engaging the tapering face ofthe head, said sleeve engaging the body, and means maintaining the endof the sleeve and face of electrode in firm contact, said sleeve andcircular head forming a peripheral concave groove which, with the body,forms an annular chamber having a gap. t

3. In a spark plug, a metal body having a socket at its upper end, aninsulator sleeve mounted in the lower part of the body projectingthrough the socket, a central electrode in the sleeve projecting abovethe same,

.and an insulator cap engaging the socket and the central electrode andsecured by the latter, said insulator cap and socket forming an annularchamber about the sleeve, the top of the cap being spaced from the topof the sleeve whereby a portion of the central electrode is'in the saidchamber, said chamber having openings in the lower and upper parts ofthe same whereby an air current is created therethrough and whereby thepart of the electrode within said chambervis subject to the directeffect of the cool- I ing air current. .7)

4. In a spark plug, a central electrode, an insulator over the lowerpart of the electrode, and means forming a chamber about the upperportion of the insulator and the upper part of the electrode and securedby the latter, said chamber havin means for causing an upward aircurrent t erethrough whereby the upper part of the electrode not coveredby the insulator is subject to the cooling effect of the air current.

THEOPHILE ELPHEGE PONSOT- Witnesses CHAS. P. PiuassLY, GEORGES BRAUN.

